Remember y'all ("you all") - you're ("you are") using "C/A Code"
as opposed to "P Code" to do this position determination, too!

C/A - Course/Acquisition Code, used initially to "lock-in"
(acquire) on the GPS SS signal *from which* one would normally
(as originaly envisioned) transitioning to using "P Code".

Chip rate for C/A code is 1.023 MHz

P Code - precision Code. Used for *precise* postioning. What is
currently being done with C/A code alone is way past the orgiginal
intentions of the GPS system designers!

Chip rate for P Code is 10x the C/A code rate, or 10.23 MHz.

*Nor* are you using [the] L2 [frequency] of 1227.6 MHz to account
for/offset the effects of RF transmission through the atmosphere ...

All in all, civilian applications are accessing only *a fraction* of
what the GPS system *is* currently supplying in the way of capability
and signals to the military (and certain qualified civilian applications).

  RF Jim (Veteran of the GPS-HDUE (High Dynamic User Equipment) program at
TI)


----- Original Message -----
From: "Alan B. Pearce" <A.B.Pearce@RL.AC.UK>
To: <PICLIST@MITVMA.MIT.EDU>
Sent: Friday, September 06, 2002 3:28 AM
Subject: Re: [EE]:Barometer & Altimeter


> >Thats not too bad, the average aircraft altimeter is +/- 75 feet. Even
> >after we ran them through the shop they were never dead on accurate.
>
> Yeah, if you get a GPS receiver where you can get at the raw data, and
leave
> the aerial sitting at a stable point for an hour or so, and collect data,
it
> is quite revealing how the "position" wanders. And this is with SA turned
> off :)
>

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